Many electronic devices, networks, and physical buildings include security features to prevent unauthorized access. For example, an electronic device can include a biometric sensing device, such as a fingerprint sensing device, that is used to verify a user's identity by determining whether captured biometric data matches known biometric data of an authorized user. The user is given access to the electronic device when the captured biometric data matches the known biometric data.
The performance of some biometric sensing devices may be adversely affected by conditions unrelated to the biometric sensing device itself. For example, a fingerprint sensing device can be sensitive to contaminants on a user's finger. Contaminants such as grease, lotion, dirt, sweat, and food particles on a finger can degrade a captured fingerprint image, which can prevent a fingerprint sensing device from matching the captured fingerprint image to a known fingerprint image. Alternatively, a finger contacting an input surface of the fingerprint sensing device with too much or too little pressure can reduce the quality of the captured fingerprint image and prevent the fingerprint sensing device from recognizing the user.